Fully-automatic, robot-assisted camera guidance susing positions sensors for laparoscopic interventions

ABSTRACT

In a method and operating system for conducting a surgical intervention, respective position sensors are mounted at a laparoscope and a surgical instrument used to conduct the intervention, and a navigation system is supplied with orientation information from these position sensors. Based on this orientation information, the navigation system automatically controls a robot arm, to which the laparoscope is mounted, to always maintain the surgical instrument in the field of view of the laparoscope.

[0001] The present invention is directed to an operating system for theimplementation of operative interventions, as defined in the preamble ofthe attached claim 1, and to a method for the follow-up of a laparoscopeattached to a robot arm for the visualization of operativeinterventions, as defined in the preamble of the attached claim 7.

[0002] Minimally invasive surgery is gaining more and more significanceas an alternative to an open surgical intervention. These interventionsare a matter of operating methods wherein operations are implementedwith the smallest possible operation wounds.

[0003] In specific fields of this minimally invasive surgery, forexample in laparoscopic interventions wherein instruments are introducedinto the abdominal region of the patient through small entry openingsand are guided and operatively utilized therein by a surgeon, thenecessity derives that the instruments be visualized on an externalpicture screen with a camera (laparoscope) additionally introduced intothe abdominal region. For example, the operating technique is currentlyroutinely utilized in the resection of the gallbladder. The surgeonthereby monitors the movement of the instruments only via the picturescreen.

[0004] In the Prior Art, the camera is guided during the intervention byan operating (OP) assistant, who assists the surgeon. In addition to theneed for additional personnel and the costs that are thereby incurred,however, the following problems arise due to the manual camera guidance:

[0005] The surgeon and the assistant guiding the camera must collaboratein the closest possible proximity and with the utmost degree ofconsultation during the operation. The assistant must often workpredictively since he/she must not only acquire the current position ofinstruments but must also support the planned instrument guidance of thesurgeon.

[0006] The camera guidance becomes imprecise and restless given flaggingattention and fatigue on the part of the assistant, particularly givenoperating procedures that last a long time. Further, the instructionsthat the surgeon gives the camera-guiding OP assistant must be veryprecise. These instructions can sometimes be misinterpreted.

[0007] Moreover, camera guidance generally does not require any highlyqualified training, so that operating assistants do not approach thistask all too gladly.

[0008] On approach for minimizing the described problems is comprised infixing the camera with instrument mounts. However, the follow-up of thecamera by an OP assistant during the operation is thereby noteliminated.

[0009] The use of a robot with whose assistance the laparoscope isinteractively controlled and moved by the surgeon is also known. Giventhis method, however, the surgeon must additionally concentrate on thecontrol of the camera.

[0010] Another approach is disclosed by U.S. Pat. No. 5,820,545, “Methodof Tracking a Surgical Instrument with a Mono or Stereo Laparoscope”.The surgical instruments introduced into the body are thereby providedwith color-coded markings. These markings are detected by the cameraintroduced into the body, whereby the camera (laparoscope) is positionedsuch with the assistance of a robot that the surgical instruments guidedin the operation are also in the field of view of the camera. When,however, the distance of the surgical instruments from the introducedcamera is also to be regulated by the robot, then the use of a stereocamera or, respectively, of a stereo laparoscope is necessary, i.e. of acamera having two optical devices.

[0011] This method, however, has the disadvantage that the instrumentsmust always be in the field of view of the camera for the follow-up ofthe camera since, otherwise, the camera loses the position of theinstruments. Moreover, the follow-up of the camera can be deteriorateddue to contamination of the color markings (for example, with blood).

[0012] WO 97/29709 A1, “Medical Procedures and Apparatus Using IntrabodyProbes”, discloses a method and an apparatus wherein an instrument probeis guided through the body of a patient. The position of this instrumentprobe relative to another probe situated in the body of the patient isthereby determined, and the instrument probe is guided through the bodybased on the identified position relative to one another.

[0013] Cinquin, P. et al., “Computer Asisted [sic] MedicalInterverventions [sic]”, IEEE Engineering in Medicine and Biology,May/June 1995, pages 254 through 263, describes computer-assistedoperative interventions upon employment of position and shape sensors.

[0014] It is thus the object of the present invention to offer anoperation system for the implementation of operative interventionsaccording to the preamble of the attached claim 1 and a method appliedin this operation system for the implementation of operativeinterventions according to the preamble of the attached claim 7 whereinan exact, automatic positioning of the laparoscope with a robot isenabled.

[0015] This object is achieved by an operation system for theimplementation of operative interventions according to the attachedclaim 1 and by a method applied in this operation system for thefollow-up of a laparoscope attached to a robot arm according to theattached claim 7.

[0016] According to the present invention, the laparoscope introducedinto the body is fully automatically controlled or, respectively,re-adjusted by a robot that receives its commands from a controlcomputer. The follow-up of the laparoscope ensues on the basis of theidentified positions of the surgical instrument, so that the surgicalinstrument is always located in the field of view of the laparoscope.

[0017] First, the inventive, automatic camera guidance eliminates themanual camera guidance by an assistant that is fraught with thedescribed disadvantages. Second, the surgeon can concentrate fully onhis/her actual task, i.e. the guidance of the surgical instruments.

[0018] The employed navigation system having sensors attached to thelaparoscope and to the surgical instrument can be a matter ofcommercially available optical systems (for example, Polaris system ofthe Northern Digital company), electromagnetic systems (for example,electromagnetic Bird system of the Ascension company) or of systemsbased on acoustic waves.

[0019] Given employment of optical systems, care must be exercised tosee that the position sensors are extra-corporeally attached, i.e. thatthe position sensors must be situated outside the body during theoperative intervention, in order to enable a optical connection to atransmitter or, respectively, to one another.

[0020] Given the electromagnetic and sound-based systems, the positionsensors can be attached either extra-corporeally as well as to the tipor, respectively, in the proximity of the tip of the laparoscope or,respectively, of the surgical instrument.

[0021] Given the extra-corporeal fastening, only rigid instruments canbe employed wherein the received coordinates of the extra-corporeallyattached sensors are converted onto the instrument tip by means of acalibration.

[0022] Given fastening of the position sensors to the tip or,respectively, in the proximity of the tip of the laparoscope or,respectively, surgical instrument, the position sensors areco-introduced into the body in the intervention. This has the advantagethat flexible instruments can also be utilized. However, theseinstruments with position sensors also occupy more space in the body.

[0023] The present invention is preferably employed in minimallyinvasive, laparoscopic interventions.

[0024] For example, a robot of Computer-Motion, Goleta, Calif., USA, canbe utilized for the robot that guides the camera.

[0025] The present invention is explained in greater detail below on thebasis of a preferred exemplary embodiment with reference to the attachedFIGURE, whose sole FIG. 1 schematically shows an inventive operationsystem.

[0026] As shown in FIG. 1, the camera or, respectively, the laparoscope5 is introduced into the body of the patient, for example in the regionof the epigastrium in FIG. 1, and is moved with a robot arm 10 with theassistance of the robot 4—the laparoscope 5 is thereby fixed to therobot arm 10 via an instrument mount 8.

[0027] The laparoscope 5 as well as one or more surgical instruments 6are provided with position sensors 7 that generate orientationinformation with whose assistance the positions of the laparoscope 5 andof the surgical instrument 6 can be calculated in the navigation system3 and forwarded to a control computer 1. The position acquisition andcalculation can thereby ensues continuously or in intervals.

[0028] The example of FIG. 1 proceeds on the basis of an electromagneticnavigation system wherein an electromagnetic field 9 is emitted by anemitter 2 that is connected via an interface 12 to the navigation system3 or, respectively, a central unit of the navigation system. Thiselectromagnetic field is detected by the position sensors 7, whichgenerate the orientation information on the basis of the electromagneticfield 9. The spatial positions and dihedral angles of the laparoscopeand of the surgical instrument or instruments 6 or, respectively, theirspatial positions relative to one another can be very precisely detectedwith the assistance of the position sensors 7. These spatial positionsand angle information are acquired by the control computer 1, whichsubsequently drives the robot 4 such and, thus, aligns the laparoscope 5such that all surgical instruments 6 to be monitored are in the field ofview of the camera, whose images are output on a picture screen, and arethus in the field of view of the surgeon.

[0029] The present invention is suitable for employment both with amono-laparoscope (having one optics) as well as with astereo-laparoscope (having two optics).

[0030] The control computer 1 sends the commands for the follow-up ofthe laparoscope 5 to the robot 4 via an interface 13. On the basis ofthe commands received from the control computer 1, the robot 4re-adjusts the laparoscope 5 secured to the robot arm 10 in conformitywith the movements of the surgical instrument 6 guided by the surgeon.

[0031] With the assistance of the articulated arn 10, the movement ofthe laparoscope 5 can ensue in six degrees of freedom: right-left,up-down, near-far, incline, tilt, turn. It is thereby possible toexclude a specific plurality of degrees of freedom. This is especiallyimportant when a movement of the laparoscope 5 in specific directions orby specific dihedral angles would jeopardize the operation safety orwhen the surgical instrument 6 is only guided in a specific region ofthe operating field.

[0032] The control computer 5 acquires the spatial positions anddihedral angles of the laparoscope 5 (camera) and of the surgicalinstruments 6 either continuously or at intervals on the basis of theposition sensors 7 attached thereat. When the control computer 1recognizes that laparoscope 5 and surgical instrument 6 are in positionswherein the surgical instrument 6 cannot be acquired by the camera, thecontrol computer 1 gives the command to the robot 4 via an interface 13(for example, serial or parallel) to move such that the surgicalinstrument 6 is located in the middle or in a defined region of thecamera's field of view. The distance between the laparoscope 5 and thesurgical instrument 6 can likewise be regulated such in this way thatthe distance does not downwardly or upwardly transgress a prescribabletolerance interval. The acquisition of the spatial coordinates of thelaparoscope 5 and of the surgical instrument 6 and the correspondingdrive of the robot arm 10 is thus executed in a servoloop.

1. Operation system for the implementation of operative interventions,comprising a laparoscope (5) attached to a robot arm (10) forvisualizing the interventions, a surgical instrument (6) for theimplementation of the interventions, characterized by a respectiveposition sensor (7) at laparoscope (5) and surgical instrument (6) forgenerating orientation information, and by a navigation system (3) fordetermining the positions of laparoscope (5) and surgical instrument (6)on the basis of the orientation information generated by the positionsensors (7), whereby the laparoscope (5) is automatically re-adjustedsuch by the robot arm (10) with the assistance of the identifiedpositions that the surgical instrument (6) is located in the field ofview of the laparoscope (5).
 2. Operation system according to claim 1,characterized in that the navigation system (3) is based on acousticwaves.
 3. Operation system according to claim 1, characterized in thatthe navigation system (3) is based on electromagnetic waves. 4.Operation system according to claim 1, characterized in that thenavigation system (3) is based on optical waves.
 5. Operation systemaccording to one of the claims 1 through 4, characterized in that theposition sensors (7) are attached to the tip of the laparoscope (5) or,respectively, of the surgical instrument (6).
 7. Operation systemaccording to one of the claims 1 through 5, characterized in that theposition sensors (7) are extra-corporeally applied to the laparoscope(50 or, respectively, to the surgical instrument (6).
 7. Method for thefollow-up of a laparoscope (5) attached to a robot arm (10) forvisualizing operative interventions, having a surgical instrument (6)for the implementation of the interventions, comprising the steps:generating orientation information of laparoscope (5) and surgicalinstrument; determining the positions of laparoscope (5) and surgicalinstrument (6) and the basis of the generated orientation information;and automatic follow-up of the laparoscope (5) with the assistance ofthe identified positions such that the surgical instrument (6) islocated in the field of view of the laparoscope (5).
 8. Method accordingto claim 7, characterized in that it is utilized in minimally invasivesurgical interventions.